1. Field of the Invention
The invention relates to apparatuses and methods for converting information from a polar coordinate system into a Cartesian coordinate system.
2. Prior Art
In many fields, such as radar and ultrasound, sensing of parameters occurs at a plurality of polar angles. In some applications it is desirable to present the sensed information in a Cartesian form since the information is more meaningful when laid out in orthogonal coordinates. This is particularly true where an orthogonal transform is used to interpret the information such as a Fourier transform. In other cases, a Cartesian coordinate system is preferred since it may be readily displayed on commonly available raster scanned displays. Numerous apparatuses and methods are known for converting polar coordinate data into Cartesian coordinate data. Some of these systems are extremely complicated and require too many computations to provide a practical real-time display. Other systems provide distorted and non-uniform displays.
As will be seen, the present invention provides an even, undistorted display with a relatively simple apparatus. The tangent and secant functions are employed for coordinate conversion and data selection.